The ARSIS concept in image fusion: an answer to users needs

International audienceThe ARSIS concept (from its French name "amélioration de la résolution spatiale par injection de structures" that means improvement of the spatial resolution by structure injection) is briefly presented. It offers a framework for the synthesis of multi-modality images at highest spatial resolution by fusion of two sets of images. This concept is comprised of three types of models. These different types are introduced and a set of solutions for implementation proposed. Four solutions are detailed and applied to a satellite Ikonos image of the city of Hasselt, Belgium. The fusion products are analyzed visually and quantitatively. These analyses enhance the benefits of offering a set of solutions to remote sensing end-users in order to fulfill their needs

Data fusion of remotely sensed images using the wavelet transform : the ARSIS solution

ISSN 0277-786XInternational audienceEarth Observation satellites are often considered to deliver a high spatial resolution image and a set of high spectral resolution images with a lower spatial resolution. Users often want to take advantage of both the high spatial and high spectral resolutions. The ARSIS concept was specially designed to fulfill this requirement and to produce high spectral resolution images with the best spatial resolution available in the set of images with respect to the original spectral content. This concept is based on the wavelet transform and the multiresolution analysis. In this paper, the concept is presented and the different parameters are discussed. Examples of application of ARSIS to real case- studies are provided. Perspectives of use of such a concept are proposed and the benefits to user discussed

Urban street mapping using quickbird and Ikonos Images

International audienceThis article addresses the problem of urban street mapping from new high resolution satellite images. The proposed algorithm is divided in two sequential modules: a topologically correct graph of the street network is first extracted, and streets are then extracted as surface elements. The graph of the network is extracted by a following algorithm which minimizes a cost function. The surface extraction algorithm makes use of specific active contours (snakes) combined with a multiresolution analysis (MRA) for minimizing the problem of noise. This reconstruction phase is composed of two steps: the extraction of street segments and the extraction of street intersections. Results of the street network extraction are presented on Quickbird and Ikonos images. Future prospects are also expose

Comparison of different algorithms for the improvement of the spatial resolution of images

International audienceThis paper presents a comparison of the most frequently used methods for improving the spatial resolution of images. Several methods have been proposed for the merging of high spectral and high spatial resolution data in order to produce multispectral synthetic images having the highest spatial resolution available within the data set, and close to reality. The methods under consideration are Brovey transform, Intensity Hue Saturation (IHS), Principal Component Analysis (PCA), P+XS (from CNES) and four methods using the ARSIS concept, including the High-Pass Filtering (HPF). The duplication of pixels is also performed, in order to assess the benefits of fusion process. The present communication discusses the methods, their advantages and disadvantages

Fusion d'images HRV de SPOT panchromatique et multibande à l'aide de la méthode ARSIS : apports à la cartographie urbaine

ISBN 2-920021-74-5International audienceL'objectif de cette communication est de présenter une nouvelle méthode permettant la production d'images à haute résolution spatiale, réunissant les qualités de la haute résolution spatiale et de la haute résolution spectrale des satellites d'observation de la Terre et plus particulièrement du capteur HRV de SPOT pour la cartographie urbaine. Les techniques de cartographie urbaine s'appuient sur des algorithmes de classification, dirigée ou non. La haute résolution spatiale ayant, pour cette application, un intérêt prépondérant, des méthodes permettant d'améliorer la résolution spatiale des images multibandes XS ont été développées. Une analyse de ces méthodes a montré qu'elles ne respectaient pas le contenu spectral original des images. La méthode ARSIS (amélioration de la résolution spectrale par injection de structures) a été développée pour fournir des images multibandes à haute résolution spatiale (dans ce cas 10 m). Elle permet la préservation de l'information originale de ces images et, par conséquent, d'améliorer l'efficacité des classificateurs. Elle s'appuie sur la transformée en ondelettes et l'analyse multirésolution, qui sont brièvement présentées. Une démonstration de cette méthode est présentée. Une évaluation quantitative a montré que la méthode ARSIS fournit de meilleurs résultats que les autres méthodes en termes de préservation de la qualité spectrale des images. Des classifications réalisées sur les données originales et sur les images résultant de la fusion sont comparées

Different implementations of the ARSIS concept to fulfill users needs

International audienceThere is a need for synthetic products that simulate satellite multispectral data at a higher spatial resolution. The users needs are various and somehow opposite: needs of high spatial resolution for accurate geometrical description of objects and needs for high spectral resolution for accurate spectral content and subsequent classification process. The ARSIS concept (from its French name "amélioration de la résolution spatiale par injection de structures" that means improvement of the spatial resolution by structure injection) permits to construct such synthetic products by fusion of two sets of data, namely panchromatic images at high spatial resolution and multispectral images at lower spatial resolution. It offers a framework wherein different models can be combined to form different solutions to better satisfy the users needs. An example is given of an Ikonos image of the city of Hasselt, Belgium

Merging SPOT-P and KVR-1000 for updating urban maps

International audienceThis communication presents a method allowing the combination of images acquired on the same area with different dates for updating urban maps. This method makes use of two mathematical tools, the wavelet transform and the multiresolution analysis which are shortly introduced. An example is provided in Jeddah (Saudi Aradia) for the updating of a KVR-1000 image by a SPOT panchromatic image acquired at a more recent date. Due to the difficulty to obtain KVR-1000 images at recent dates, this method allows the combination of the high spatial resolution of this kind of images and the regular acquisition of images by the different Earth observation satellites

Data fusion for a better knowledge of urban areas

International audienceThis paper demonstrates the benefits of fused products for the analysis and mapping of urban areas. The fused products result from the synthesis of multispectral images at higher spatial resolution h, starting from a panchromatic image at resolution h and multispectral images at a lower resolution l. The application of the method ARSIS- RWM to the city of Marseille is discussed. It is further demonstrated that synthetic images may support further image processing dealing with the high frequencies

Comment. Liu "smoothing filter based intensity modulation: a spectral preserve image fusion technique for improving spatial details".

International audienceWe discuss a critical point of the paper. It is shown on the one hand that the author of this paper has mistaken the change of spectral content with the change in spatial resolution, and on the other hand, that the protocol used to establish the advantages of his smoothing filter-based intensity modulation (SFIM) technique over other methods is not appropriate at all. Though the SFIM technique has its merits, the article does not demonstrate its expected qualities